I happened to have noticed this today. Apparently in future ABP updates, the devs can set it so that blocked ads on a page will be replaced with ABP's acceptable ads. There is no word if users will be able to opt-out of this program since most users use adblock not only as a security measure, but to deal with webpages that have ads that are annoying and slow down loading of the sites they want to access (drains mobile data / data plans too!).

Any thoughts on this? The marketplace is now in beta with a full release (and planned ABP update) due later this year.

That's for the original version of acceptible ads. I was speaking about the marketplace that's now in beta. Acceptible Ads 2.0 if you will. I didn't see any info if they would make the marketplace mandatory for all or if they would continue to let users opt-out in this future update.

If that's not clear enough, let me put this a different way. As far as I can see, as a user of uBlock Origin, I could opt in to this right now if desired, and I'd have exactly the same experience as users of Adblock Plus who didn't opt out.

What else do you think there is to it?

*Always* check the changelogs BEFORE updating that important software!